Add patched zeromq-haskell library to travis build.

As required patches were not yet pushed upstream, we
have to use our own fork.

Add more contraints to library build.

Build dependencies in one pass.
reduce number of test passes for the slow pc
Take care of cleanup procedure.

We should wait for subthreads that uses sockets to exit
before closing a socket. This was fixed.
Also LocalEndPoint state was hidden when EP is going
down.

Add mask to finalizer, otherwise endpoint may not be closed.